Systems, methods and machines for aligning and assembling single-axis tracker foundations

ABSTRACT

An automated control system for a screw anchor driving and truss assembly machine. A positioning subsystem determines an orientation of a machine mast&#39;s driving axis relative to an intended drive axis and controls the mast to be positioned so that the mast&#39;s driving axis is aligned with the intended drive axis of the screw anchor foundation component. After a pair of adjacent screw anchors are driven, the controller causes motion controllers to orient the mast so that an alignment jig for supporting truss apex hardware is held in place relative to the driven screw anchors at a predetermined point in space above them so that upper leg sections can be sleeved over connecting portions of the apex hardware and down on to the driven screw anchors.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. utility patent application Ser. No.16/835,256, filed on Mar. 30, 2020, titled, “Systems, methods andmachines for aligning and assembling truss foundations,” now U.S. Pat.No. 11,479,938, which, claims priority to U.S. provisional patentapplication No. 62/826,844 filed on Mar. 29, 2019, titled, “Automatedwork point alignment for anchored A-frame foundations and relatedsystems and methods,” the disclosure of which are all herebyincorporated by reference in their entirety.

BACKGROUND

The applicant of this disclosure has invented a novel foundation systemfor single-axis trackers and other structures to replace conventionalmonopile foundations. Known commercially as EARTH TRUSS, this systemreplaces H-piles with moderately sloped A-frame-shaped trusses. EachA-frame-shaped truss is formed from a pair of adjacent tubular screwanchors driven into the ground at angles to one another on either sideof a North-South oriented tracker row. An upper leg is coupled to theend of each screw anchor, and an adapter, bearing adapter, or truss capjoins the free ends of each upper leg to complete the truss. Oneadvantage of the A-frame geometry over conventional monopiles is thatfor foundations that support non-moment connections, the A-frame takesthe foundation out of bending and instead subjects it to axial forces oftension and compression. Single structural members are very good atresisting such forces relative to their ability to resist bending,therefore much smaller, tubular members may be used to make up the trussleg. Also, because axial forces dominate, the legs can be driven toshallower embedment depths. The net result is that by using a trussfoundation the tracker can be supported with less steel.

One reason that monopiles have dominated the market for single-axistracker foundations is their simplicity. Even though they are inherentlywasteful, it is relatively easy to install rows of plumb-drivemonopiles. By contrast, assembling a truss foundation requiresspecialized machines that can drive a pair of adjacent anchors atnon-plumb angles. It also requires the assembly of two-piece legs thatare interconnected with apex hardware that must be aligned with respectto the site plan and to other truss foundations in the same row.Therefore, in order to maximize the competitiveness of truss foundationsrelative to monopiles, automated machine control techniques must be usedto assist an operator in aligning, installing, and assembling trussfoundations so that installation complexity does not erode the materialsavings provided by truss foundations.

To that end, it is an object of some embodiments of the disclosure toprovide systems, methods, and machines for automatically aligning ascrew anchor driving machine to drive screw anchors along an intendeddrive axis. It is a further object of other embodiments of the inventionto provide systems, method, and machines for automatically orienting analignment jig to enable a truss foundation to be assembled so that therotational axis of the single-axis tracker is aligned with respect to apredetermined point in space. These and other objects, features andadvantages of the present disclosure will become apparent from thefollowing detailed description of illustrative embodiments thereof,which is to be read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a prior art truss foundation supporting a portion of asingle-axis tracker;

FIG. 1B shows the components of the truss foundation shown in FIG. 1A;

FIG. 2A shows a bearing adapter according to various exemplaryembodiments usable with a truss foundation such as that as shown in 1A;

FIG. 2B shows a bearing support according to various exemplaryembodiments usable with a truss foundation such as that shown in 1A;

FIG. 3A shows a side view of a machine for installing and assemblingtruss foundation components according to various embodiments;

FIG. 3B shows a mast view of a portion of the machine for installing andassembling truss foundation components according to various embodiments;

FIG. 4 is a force diagram showing how lateral loads are translated in atruss foundation;

FIG. 5 is a coordinate system showing the axes of drive axis alignmentfor a truss installation and assembly machine according to variousembodiments of the invention;

FIG. 6 is a line diagram showing portions of a single-axis trackersupported by truss foundations;

FIG. 7 shows a portion of a machine mast for installing and assemblingtruss foundations according to various embodiments of the invention;

FIG. 8 shows a portion of a machine mast for installing and assemblingtruss foundations according to various other embodiments of theinvention;

FIG. 9 is a system diagram showing components of an automated system foraligning a drive axis of a machine mast with an intended drive axisaccording to various embodiments of the invention;

FIG. 10 is a flow chart detailing the steps of an automated method fortruss installation and assembly according to various embodiments of theinvention;

FIG. 11 is a flow chart detailing the steps of an automated method foraligning drive axis of a screw anchor driving machine with an intendeddrive axis so that the anchor points a predetermined point in space; and

FIG. 12 is a line diagram showing a pair of intended drive axes foradjacent screw anchors according to various embodiments of theinvention.

DETAILED DESCRIPTION

The following description is intended to convey a thorough understandingof the embodiments described by providing a number of specificembodiments and details involving A-frame-shaped truss foundationssupporting single-axis solar trackers. It should be appreciated,however, that the present invention is not limited to these specificembodiments and details, which are exemplary only. It is furtherunderstood that one possessing ordinary skill in the art in light ofknown systems and methods, would appreciate the use of the invention forits intended purpose.

Turning now to the figures, where like elements are designated with likenumbers, FIG. 1A shows truss foundation 10 supporting a portion of anexemplary single-axis tracker. FIG. 1B shows the elements of trussfoundation 10 in FIG. 1A as individual components. The tracker shownhere is a conventional bottom-up type tracker where the torque tube issupported in a series of bearings that enable it to rotate about its ownaxis. Although this design is employed by many tracker makers, the oneshown in FIG. 1A approximates the torque tube and bearing assembly ofthe DuraTrack HZ single-axis tracker manufactured and sold by ArrayTechnologies, Inc. of Albuquerque, N. Mex. As discussed in the contextof FIG. 2A, truss foundation 10 may also support a top-down style oftracker where the torque tube is suspended from a bearing pin andinstead swings through an arc about the pin.

Truss foundation 10 consists of a pair of adjacent angled truss legswhose above-ground ends are joined by adapter 20. The truss legs aremoderately angled with respect to the ground by an angle θ that mayrange from 55-degrees up to 72.5-degrees corresponding to a separationangle between the legs a in range of 70-degrees down to 35-degrees. Eachtruss leg consists of screw anchor portion 11 extending below ground, adriving coupler 12 at the upper end of each screw anchor 11, and anupper leg portion 13 that attaches to one of screw anchors 11 viadriving coupler 12. Though not shown in the figure, screw anchor 11 mayhave an external thread form at its lower end and may extend severalfeet into the underlying ground. In various embodiments a crimper may beused to compress upper legs 13 around couplers 12 to unify the truss,however, other types of mechanical fasteners may also be used.

Adapter or bearing support 20 is shown as a unitary structure withconnecting portions 21 that extend down and into the top end of eachupper leg 13. Connecting portions 21 may also be secured to the leg witha crimp connection by placing a crimping drive over the portion of eachupper leg 13 covering one of the connecting portions 21. Adapter 20 mayhave a brace or gusset plate 22 that provides additional support. Asshown in FIGS. 1A and 1B, exemplary tracker bearing assembly 30 includesa main body portion that sits on and is attached to support surface 23of bearing support 20 via a pair of bolts or other suitable mechanicalfasteners. Torque tube 33 is centered within bearing 30 via bearinginsert 32. Bearing insert 32 enables the torque tube to have a morerigid faceted geometry and still fit within the circular bearing openingof bearing assembly 30. It also prevents metal-to-metal contact withinthe bearing. In real-world conditions, a single tracker row may extendover 300-feet and include foundations such as truss foundation 10 every20-30 feet.

In the example of FIG. 1A, the rotational axis of the tracker, thecenter of torque tube 33, is positioned at the work point of truss 10.This is shown by the arrows through the center of each upper leg portion13 that point directly at the center of torque tube 33. As discussedherein, by aligning the tracker's rotational axis with the work point ofeach truss, lateral loads are maximally converted into axial forces oftension and compression in the truss legs. However, as discussed ingreater detail in the context of related U.S. patent application Ser.No. 16/824,550 (the '550 application), alignment of the rotational axiswith the work point may not be advantageous for foundations that mustalso resist moments in addition to lateral loads. In such cases, it maybe preferred to offset the rotational axis below the truss work point.The disclosure of the '550 application is hereby incorporated byreference in its entirety. The various principles disclosed herein areequally relevant to applications where the rotational axis must bealigned with the work point as well as ones where the rotational axismust be aligned to a point in space that may be offset from the trusswork point.

FIG. 1B shows the individual components making up exemplary trussfoundation 10. The base component is screw anchor 11. Screw anchor 11 isa section of substantially uniform diameter, open pipe of precut length(e.g., 1-meter) that has an external thread form beginning at the lowerend extending up a portion of the shaft and driving coupler 12 fixed atthe opposing end. Driving coupler 12 may be a separate cast piece thatis welded or otherwise attached to the upper end of screw anchor 11. Invarious embodiments, it is engaged by a chuck of a screw anchor drivingmachine so that torque and down force may be transferred to anchor 11 todrive it into underlying ground. Also, driving coupler 12 provides anattachment point for upper leg portion 13. In various embodiment, anupper leg 13 is sleeved over coupler 12 until it rests on the drivingfeatures which, as shown in FIG. 1B, have a larger diameter than therest of the coupler. They act as stop to limit the extent of penetrationof the coupler into the upper leg. The apex component of trussfoundation 10 that joins the free ends of each upper leg 13 is bearingsupport or adapter 20. Bearing support 20 has connecting portions 21that extend away at angles that match the intended angles of each trussleg.

In various embodiments, and as discussed in greater detail herein, truss10 is assembled by driving a pair of screw anchors into the ground atangles to one another to point at a common point in space, such as thework point of the truss. Then, bearing support 20 is held in place by ajig on a mast of the anchor driving machine at the orientation thataligns with other bearing supports in the same row. An operator may thensleeve an upper leg over each connecting portion 21 of bearing support20 until there is sufficient clearance to sleeve back down over one ofthe respective couplers 12. In various embodiments, the overlap betweenconnecting portions 21 and upper legs 13 and between upper legs 13 andcouplers 12 is intentionally sloppy to allow for some misalignmentbetween the drive axis of screw anchors 11 and their intended driveaccess prior to crimping so that bearing support 20 will support thetracker's rotational axis at the desired point in space. In variousembodiments, a crimper is used at the four connection points to unifythe truss foundation at the proper orientation, thereby removing theslop.

Turning now to FIG. 2A, this figure shows a portion of a trussfoundation supporting a portion of another single-axis tracker. In thiscase, the single-axis tracker is a mechanically balanced top-down styletracker such as the NX series of single-axis trackers manufactured andsold by NEXTracker Inc., of Fremont, Calif. Although the actual trackeris not shown in the figure, in such a tracker the torque tube hangs froma bearing pin above it rather than rotating with a bearing about its ownaxis. To accomplish this, the drive motor is offset from the rest of thetorque tube to be axially aligned with the bearing pin rather than thetorque tube so that as the motor turns, the tube swings through an arcabout the pin. In this example, the truss apex hardware used to supportsuch a tracker may combine bearing and support function into a singlestructure designated herein as a bearing adapter. Bearing adapter 40joins the free ends of upper legs 13 to complete the A-frame-shapedtruss, enabling lateral and vertical loads to be resisted in the legs asaxial forces of tension and compression, and it aligns the tracker'saxis of rotation, in this case, the bearing pin, with the work point ofthe truss. Adapter 40 also limits the extent of the arc the torque tubecan swing in both the East and West directions to resist unintendedmovement due to external forces.

Other than replacing bearing support 20 with bearing adapter 40, thefoundation supporting the single-axis tracker in FIG. 2A is essentiallythe same as that shown in the context of FIGS. 1A and B. Each truss legconsists of upper leg portion 13 joined to the top end of screw anchor11 via driving couplers 12. Bearing adapter 40 joins the truss legs toform a unitary A-frame-shaped truss but also provides the features ofthe NEXTracker bearing house assembly (BHA) shown with dotted lines FIG.2B. As shown, bearing adapter 40 has a cardioid-shaped frame 41 with apair of connecting portions 42 extending below into each upper leg 13.Cardioid-shaped frame 41 also has a cusp portion 44 that includesbearing 45. In the NEXTracker ecosystem, a bearing pin sits in thebearing and one or more torque tube brackets suspend the torque tubefrom the bearing pin. Therefore, the rotational axis is not the torquetube itself but rather the bearing pin. Cardioid-shaped frame 41 has apair of opposing lobes that provide clearance for the torque tube toswing through its arc as the panels are moved from East-facing toWest-facing each day. Gusset plate 43 between connecting portions 42provides additional rigidity to frame 41.

As seen in FIG. 2A, even though the torque tube rotates about a bearingpin seated in bearing 45, the truss legs still point at the truss workpoint, in this case the center of bearing 45. In such a system, thebearing does not resist rotation of the tracker and therefore thebearing adapter 40 provides a largely non-moment connection to thetracker. The only exception is that when the tracker is at the maximumtilt angle (typically 55 to 60-degrees), any additional external forcesmay cause the torque tube to contact and bear against the inside surfaceof one of the lobes of cardioid-shaped frame 41. This will impart somemoment to the truss foundation. Otherwise, such external forces areresisted only at the foundation supporting the drive motor.

A truss foundation using bearing adapter 40 is assembled in the same wayas discussed above in the context of the foundation shown in FIGS. 1Aand B. After each screw anchor is driven into the ground along itsintended axis, bearing adapter 40 is held by an alignment jig on theinstallation and assembly machine so that the bearing is aligned withother bearings in the row (e.g., along the Y-axis, Z-axis, and in pitch,roll and yaw). If the rotational axis is to be aligned with the trusswork point, a design parameter that will be known beforehand, the jigwill hold the adapter 40 so that its bearing is at that position.Otherwise, if it is to be offset, it will hold it a fixed distance froma predetermined point in space.

FIG. 2B shows bearing support or adapter 50 according to various otherembodiments of the invention. Like bearing adapter 40, bearing support50 is also designed to work with a top-down tracker system, however,this component relies on the tracker maker's bearing housing assembly(BHA) rather than incorporating the function of the bearing into thebearing support. Support 50 has a main body portion 51 with a pair ofconnecting portions 52 extending below and away from main body 51. Likethose on bearing adapter 40, these connecting portions are received inrespective upper legs to complete the truss. The upper side of support50 has a pair of pedestal portions 53 that support the legs of theNEXTracker bearing housing assembly (BHA), obviating the need for theright-angle brackets used to support such a tracker with a conventionalH-pile. Between pedestal portions 53 is a recessed portion 54. Invarious embodiments, recessed portion 54 may assist installation byallowing torque tube sections to be placed on bearing support 50 whilethe BHAs are attached to the torque tube. As with bearing adapter 40,support 50 is dimensioned so that connecting portions 52 match the angleof the truss legs and also enables the legs, once connected to point atthe work point of the truss, in this case, the bearing formed in theNEXTracker BHA. Because bearing support 50 does not have a bearing butrather is offset from the bearing by a known offset, depending on thetracker manufacturer, the alignment jig on the machine mast will holdbearing support 50 so that it is centered about the work point and at aknown distance below the work point so that when the NEXTracker bearinghousing assembly is attached to the top of bearing support 50, thebearing that receives the bearing pin will be aligned with the trusswork point.

FIG. 3A shows a machine for driving and assembling truss foundationsaccording to various embodiments of the invention; FIG. 3B is a close-upview looking at a portion of the machine mast. As shown in the exampleof the figures, machine 200 is a piece of heavy equipment riding ontracked chassis 201. Articulating mast 210 is connected to trackedchassis 201 via mechanical interface 205 consisting of multiplehydraulic actuators, slides, trunnions, etc., and corresponding motioncontrollers that effect movement of the mast with up to six degrees offreedom with respect to machine 200 via these elements. As shown, mast210 is an elongated boxed or beam-like structure that extends far abovemachine 201. In various embodiments, mechanical interface 205 enablesthe machine to move with respect to the machine at least in Z, Y, pitch,roll and yaw and also, in some embodiments, X, to enable the mast andits corresponding screw anchor driving axis to be aligned with thedesired location of truss foundation components to insure that eachtruss foundation in a given tracker row supports the torque tube at thedesired orientation. On level ground, this may mean supporting it to belevel and at the same height. On contoured terrain, this may meanremaining orthogonal to the torque tube and maintaining the tube along acontinuous straight axis.

Turning to 3B, mast 210 has a pair of parallel tracks or rails 211running substantially the entire length on either side. Lower crowd orcarriage 212 rides along tracks 211 to move up and down mast 210motivated by chain 214 that is attached to a lower crowd motor or othersuitable power source (not shown). In various embodiments, the lowercrowd motor may be located behind the mast (i.e., on the side of themast facing the machine) or otherwise concealed within the mast so asnot to interfere with the movement of lower crowd 212 along the mast. Invarious embodiments, and as shown in the drawings, rotary driver 220 isattached to lower crowd 212. Rotary driver 220 may be hydraulicallypowered unit with an output chuck 221 that receives a driving collar ofa screw anchor and transfers torque to the anchor via the chuck torotate it into the ground. In various embodiments, at the same time asrotary driver 220 applies torque, the lower crowd motor pulls on chain214 to transfer downforce to the screw anchor via lower crowd 212 sincerotary driver 220 is attached to it. In various embodiments, thecombination of torque and downforce are optimized via automatedclosed-loop feedback control to drive screw anchors into underlyingground without augering the soil.

Though not shown in the detail of 3B, tool driver 230, such as ahydraulic drifter or other drilling tool, may also be positioned on mast210 on a separate upper crowd or carriage so that its shaft passesthrough rotary driver 220 as well as through an attached screw anchorwhen driving. In various embodiments, this upper crowd or carriage isalso coupled to chain 214 and therefore movable up and down mast 210 bythe lower crowd motor at the same rate as lower crowd 212. However,unlike lower crowd 212, in various embodiments, the upper crowd isselectively detachable from chain 214 and movable by a separate driftmotor that enables the hydraulic drifter to the tool shaft to move at adifferent feed and speed than the feed and speed of rotary driver 220.

As seen in FIG. 3B, in various embodiments, lower crowd 212 or mast 210may include one or more alignment jigs 240 that may be used duringassembly of the truss foundation to hold the bearing support at theproper orientation, that is so that when a BHA or bearing assembly areattached, the rotational axis of the BHA or bearing assembly will passthrough the work point of the truss. In this figure, alignment jigs 240are shown as projections, however, it should be appreciated that one orpins, clamps or other structures may be used to hold the bearing supportor bearing adapter in place. As discussed in greater detail in thecontext of the remaining figures, in various embodiments, a controllerthat controls the orientation of the mast is programmed to automaticallyposition the lower crowd and/or mast 210 so that the alignment jigs 240will position the bearing support or bearing adapter at the correctlocation to be consistent with the site design and other foundations inthe same row. Rotary driver 220 must extend down below the lower end oflower crowd 212 so that the rotary driver can extend sufficiently fardown to drive screw anchors into the ground, however, it needs to be outof the way when assembly the truss. In various embodiments, alignmentjig 240 may be on a removable assembly that can be selectively attachedand removed from lower crowd 212.

Turning now to FIG. 4 , this figure is a force diagram showing howlateral loads from wind striking the array are translated into the legsof a truss foundation. Regardless of foundation type, in a single-axistracker, lateral loads are translated into the foundation via therotational axis of the system (i.e., the point that the rotating partsrotate about or within). In most single-axis tracker systems, where atorque tube is captured within a circular bearing, the torque tubeitself defines the axis of rotation. Lateral forces are transferred tothe foundation directly via the bearing assembly surrounding the tube.However, as discussed in the context of FIGS. 2A, in the NEXTRACKERsingle-axis tracker, the torque tube is offset from the axis ofrotation. The tube is attached to a tube clamp that hangs from a hingepoint formed in a torque tube clamp support. As a result, the axis ofrotation is the bearing pin, not the tube itself. When a single-axistracker is supported by a truss foundation at a point that primarilyresists lateral loads, as opposed to bending moments, the axis aboutwhich rotation occurs should ideally pass through the truss work pointto enable the lateral load to translate into axial forces of tension andcompression in the legs. Individual structural members are good atresisting axial forces relative to their ability to resist bending,therefore, the truss offers an advantage relative to single H-piles. Inthe line diagram of FIG. 4 , the work point is the intersection of animaginary line extending through the center of mass of each leg.However, achieving that may be more complicated with a truss foundationthan with a single plumb-driven H-pile because there are more componentsthat can contribute to misalignment. Therefore, the portion of theA-frame legs extending into the ground must be driven with the workpoint in mind so that each leg points at a common work point. If so, aline extending through each leg's center of mass will extend to a commonabove-ground intersection point or three-dimensional area in free space.In the case of a bottom-up tracker where the torque tube rotates aboutits own axis, at non-moment connection points, the torque tube shouldpass through the work point for each A-frame or truss foundationsupporting it. In the case of a top-down or mechanically balancedtracker, the axis of the bearing pin about which the torque tube rotatesshould pass through work point and should be oriented the same as otherbearings in the same tracker row.

FIG. 5 shows a coordinate system around a machine mast to illustrate therequired articulation to align the masts drive axis with an intendeddrive axis for the current screw anchor. At each foundation site, thatis, position along the North-South row of the tracker designated as theX-axis in the figure, the X-axis location is known in advance based onthe requirements of the tracker and the site plan. Pitch and roll aredictated by the contour of the land and the requirement of orthogonalityto the rotational axis, if present. After the machine is positioned to alocation where a truss foundation is to be installed on the X-axis, themast must be aligned with respect to the Y and Z axes as well as alignedin pitch, roll and yaw, to be consistent with other foundations in therow and/or to maintain orthogonality to the tracker's rotational axis.FIG. 6 shows a portion of a single-axis tracker 100 supported by trussfoundations where the foundations are shown as line diagrams. The figureshows the required symmetry from foundation to foundation where theplane defined by each truss foundation 110 is parallel to each otherfoundation and is orthogonal to torque tube 120. Assuming a straighttorque tube, this requires the bearings to be aligned in multiple axesto avoid putting stress on the torque tube. Therefore, in variousembodiments, the machine may determine an initial location andorientation of the mast, or a point or axis of the mast within acoordinate system, such as that shown in FIG. 5 . A programmable logiccontroller (PLC) or other microcontroller may then compare this to anintended drive axis and control one or more motion controllers effectingmotion of the mast to align the mast's drive axis with an intended driveaxis for the current foundation.

The first step of achieving foundation alignment is driving the screwanchors that make up the base of the foundation along their intendedaxis, that is, at the angle and orientation required to consistentlysupport the rotational axis of the tracker, torque tube or bearing pin,such as, for example, at the truss work point. In some cases, the driveaxis may become misaligned from the intended axis due in part to changesin soil density, mast movement, etc. In recognition of this, in variousembodiments of the invention, after the pair of adjacent screw anchorshave been driven, the microcontroller will cause the mast to orient toan alignment position where a jig on the mast is positioned with respectto a predetermined point in space, such as the truss work point, so thatthe truss can be assembled to insure that the bearing will be located atthe intended position, and misalignment of one or both screw anchors maybe effectively corrected. To that end, FIG. 7 is a partial front view ofmachine mast 210 after screw anchors 11 have been driven.

In various embodiments, the controller controlling movement of the mastwill cause mast 210 to raise alignment jig portion 240 so that it holdsbearing support 50 at respective Y, Z, pitch, roll and yaw orientationsthat will result in the BHA's bearing being aligned with other bearingsin the row when attached to bearing support 50. In various embodiments,if the bearing is to be aligned with the work point, the midlinedistance from support 50 to the bearing will be known in advance.Therefore, the controller can control the mast to elevate alignment jigportion 240 and by extension, bearing support 50 to a height H that willresult in the bearing being aligned. An operator may then sleeve anupper leg over one of the connector portions 52 of bearing support 50and then drop it down over the top of driving coupler 12. The process isrepeated for the second leg. Intentional slop at the connection pointsbetween upper legs 13 and connection portions 52 and couplers 12 willcorrect for misalignment between the anchors intended and actual driveaxes. With bearing support 50 held securely in place by alignment jigportion 240, the connections may be crimped with an external crimpingdevice to preserve the proper orientation.

Turning now to FIG. 8 , this figure is another partial front view ofmachine mast 210 after screw anchor anchors 11 have been driven. In thisexample, bearing adapter 40 is used instead of bearing support 50.Assuming intended alignment of the tracker's rotational axis with thetruss work point, the controller may control one or more motioncontrollers to orient alignment jig portion 240 to support bearingadapter 40 so that its bearing aligns with the truss work point. Withbearing adapter 40 in place, upper legs 13 may be sleeved overrespective connection portions 42 and then dropped down onto drivingcouplers 12 to complete the truss. A crimper may once again be used atthe four interconnection points to lock the truss geometry in placebefore moving the machine and mast to the next foundation location.

FIG. 9 shows exemplary system 250 for automatically aligning a drivingaxis of a mast of a foundation component installation and assemblymachine with a predetermined drive axis according to variousembodiments. The boundaries of system 250 are virtual not physical. Thedotted line around system 250 does not signify a physical arrangementbut rather the logical relationship between system elements. The centerof system 250 is programmable logic controller or PLC 260. This may be astandard programmable logic controller (PLC) or one of many commerciallyavailable microcontrollers. Storage unit 262 is communicatively coupledto PLC 260 through a wired or wireless communication interface. Invarious embodiments, PLC 260 will have its own internal non-volatilememory where it stores its control program, whereas storage unit 262 maybe used to store site-specific inputs and outputs, such as, for example,the intended location of each foundation on a job site include the workpoint, rotational axis height, type of tracker to be installed, trussleg angle, etc. as well as information generated during use of thesystem.

Module 270 is a positioning subsystem. This may include one or moreglobal or local positioning systems that receive signals from satellitesand/or local sources. In various embodiments, positioning subsystem 270generates position information that corresponds to one or more points onthe mast so that PLC 260 is able to adjust the location and/ororientation of the mast's drive axis relative to an intended drive axisfor the screw anchor currently being installed. In various embodiments,a plurality of sensors 275, labeled as Sensor₁-Sensor_(N), where N is aninteger greater than two, are distributed along the movable axes of themast to measure and/or encode movement of the mast along these axes sothat the distance traveled from a starting orientation can be monitoredand controlled by PLC 260. In addition, system 250 includes a pluralityof individual motion controllers MC₁, MC₂, . . . , MC_(N). In variousembodiments, each motion controller (MC) is connected to one or morehydraulic actuators 280 to affect movements controlled by PLC 260. Asdiscussed in greater detail in the context of the flow charts of FIGS.10 and 11 , the components of system 250 enable automated alignment ofthe mast with respect to a predetermined point in space so that anchorsmay be driven, and foundations assembled, in a consistent and repeatablemanner.

Turning now to FIG. 10 , this figure is a flow chart detailing the stepsof method 300 for truss alignment and assembly according to variousembodiments of the invention. It should be appreciated that the specificorder shown in the flow chart is not required and that in variousembodiments, the steps may be performed in a different order. Also, invarious embodiments, fewer or more steps may also be performed. Themethod begins in step 305 where jobsite data is uploaded to the machine.Jobsite data may include the location of each foundation on the arraysite, the work point height or each truss, the leg angle of each truss,as well as information specific to the type of tracker to be installed.As discussed in the context of FIG. 9 , this information may reside in astorage unit communicatively coupled to the PLC. Jobsite data may beuploaded via a wired connection to an external device, from a USB orother format data drive or wirelessly transmitted to the machine. Then,in step 310, the machine is navigated to a foundation location, that is,a point along the intended North-South row of the tracker array where atruss foundation is to be installed. Navigation may be performed by anoperator driving the machine along the tracker row, or alternatively,navigation may be performed automatically with and an automatednavigation system capable of controlling the machine to move to eachX-axis location along the North-South row based on stored informationabout the array.

In step 315, a first screw anchor is loaded onto the rotary driver ofthe machine mast. In various embodiments, after an operator presses astart button on the machine or on a remote controller for the machine,the controller causes the mast to rise vertically to enable a screwanchor to be loaded. After the anchor is loaded, the operator may pushanother button or execute another command to commence the drivingoperation for the first screw anchor. In various embodiments, inresponse to this, in step 320, the controller will determine thedifference between a current orientation of the mast's drive axis, and adesired drive axis for the current foundation component or screw anchor.Once this has been determined, the controller will control requiredmotion controllers to affect a change in the orientation of the mast'sdrive axis so that it matches the intended drive axis. This sub processis described in greater detail in the context of FIG. 11 . In step 325,the first screw anchor is driven into underlying ground to the desireddepth along the intended axis by applying torque with the rotary driverand downforce from the lower crowd. In various embodiments, thecontroller, in accordance with stored program data, will optimize themix of torque and downforce to successfully drive the screw anchor asfast as possible without augering the soil or stalling.

When the anchor has reached the desired embedment depth, operationproceeds to step 330 where the controller causes the mast to level andto raise the lower crowd and by extension the rotary driver to theloading position so that an operator may load another screw anchor. Thismay happen automatically or in response to an operator command after thedesired embedment depth is reached. Then, in step 335, the operatorpresses a button or otherwise issues a command to commence the drivingoperation for the second screw anchor. In response, the controllercauses the mast to move from its current orientation to once again alignits drive axis with the intended drive axis for the second screw anchorof the adjacent pair. Once aligned, operation proceeds to step 340 wherethe controller actuates the rotary driver and lower crowd to drive thesecond screw anchor. When the driving operation is complete, at step345, the controller reverts the mast to a plumb orientation and raisesthe lower crowd to the alignment position for the particular trackerbeing installed so that a bearing support or bearing adapter can beattached to the alignment jig on the mast and the truss foundationconstructed with the support or adapter at the correct position.

Turning to FIG. 11 , figure is another flow chart detailing the steps ofmethod 400 for automatically aligning a mast of a screw anchor drivingmachine with an intended truss leg axis so that the driven screw anchorpoints a predetermined point in space. The method begins in step 405where the controller determines the location of the mast, or a point onor axis of the mast, within a coordinate system, such as the systemshown in FIG. 5 . As discussed herein, this step may be performed with apositioning system such as a GPS receiver or other global or localpositioning system, or with a combination of two or more such systems.Once the controller receives the location information, in step 410, itis programmed to calculate the difference from its current orientationto the intended drive axis for the current anchor. The result of thiscalculation will be translated by the controller into a set of movementsrequired by the mast to align its drive axis with the intended driveaxis. In step 415, the controller issues commands to the individualmotion controllers controlling the mast's actuators (hydraulic orelectric), to use the available axes to align the mast. Alignment may beconfirmed by repeating the location determining step 405 and confirmingthat the mast's linear drive axis is sufficiently aligned with theintended axis. Alternatively, alignment may simply be mathematicallyconfirmed by measuring with linear and/or rotary encoders the movementof the machine from the initial reference location to its location afterthe mast's drive axis has been aligned with the intended drive axis.

Turning now to FIG. 12 , as seen in this figure, it is not required thata specific portion of the mast pass through the work point of the truss,but rather that the mast's drive axis overlaps with the intended firstand second axes. In other words, in the simplest case, once the machineis properly oriented at the foundation location, it would be possible todrive a screw anchor, retract the upper crowd, rotate about the workpoint, and drive a second screw anchor. In a purely mechanicallycontroller system, this may be required to insure that the first andsecond screw anchors point at a common work point. However, computerizedcontrol via the PLC enables a more robust approach where the rotationalcenter of the mast need not be about the work point as long as themast's drive axis lines up with either the first or second drive axis inthe figure.

The embodiments of the present inventions are not to be limited in scopeby the specific embodiments described herein. Indeed, variousmodifications of the embodiments of the present inventions, in additionto those described herein, will be apparent to those of ordinary skillin the art from the foregoing description and accompanying drawings.Thus, such modifications are intended to fall within the scope of thefollowing appended claims. Further, although some of the embodiments ofthe present invention have been described herein in the context of aparticular implementation in a particular environment for a particularpurpose, those of ordinary skill in the art will recognize that itsusefulness is not limited thereto and that the embodiments of thepresent inventions can be beneficially implemented in any number ofenvironments for any number of purposes. Accordingly, the claims setforth below should be construed in view of the full breath and spirit ofthe embodiments of the present inventions as disclosed herein.

The invention claimed is:
 1. A machine for constructing and assemblingsolar tracker foundations comprising: an articulating mast having atleast one rail extending along a length of the articulating mast; arotary driver controllable to travel along the at least one rail todrive at least one first foundation component into underlying groundalong a drive axis set by an orientation of the mast; at least onemicrocontroller programmed to control the articulating mast and rotarydriver to orient the drive axis set by the orientation of the mast to bealigned with a desired drive axis and to drive the first foundationcomponent into underlying ground along the desired drive axis; and analignment jig for holding a second foundation component proximate to theat least one first foundation component and relative to a known positionin a coordinate system to enable a third foundation component tointerconnect the second foundation component to the first foundationcomponent.
 2. The system according to claim 1, wherein the secondfoundation component is a tracker bearing support.
 3. The systemaccording to claim 2, wherein the known position in a coordinate systemcorresponds to a location of an approximate center of a tracker torquetube above the tracker bearing support.
 4. The system according to claim1, wherein the at least one first foundation component is a screwanchor.
 5. The system according to claim 1, wherein the at least onefirst foundation component is a helical anchor.
 6. An automated systemfor constructing and assembling foundations for single-axis trackerscomprising: an articulating mast connected to a mobile machine; a rotarydriver positioned on the mast and controllable to travel along the mastto drive a first foundation component into underlying ground along adrive axis; a microcontroller connected to a plurality of motioncontrollers, the microcontroller programmed to control the plurality ofmotion controllers to align the drive axis with a desired drive axis andto control the rotary driver to drive the first foundation componentalong the desired drive axis; and an alignment jig positioned on themast for holding a second foundation component above the firstfoundation component after the first foundation component is driven toenable a third foundation component to interconnect the secondfoundation component to the first foundation component.
 7. The automatedsystem according to claim 6, wherein the microcontroller is programmedto orient the alignment jig so that the second foundation component ispositioned with respect to the first foundation component at apredetermined point in space.
 8. The system according to claim 6,wherein the second foundation component is a tracker bearing support. 9.The system according to claim 6, wherein the second foundation componentis a bearing adapter.
 10. The system according to claim 7, wherein thepredetermined point in space corresponds to an approximate center of atracker torque tube that will be supported by the second foundationcomponent.
 11. An automated system for constructing foundations forsingle-axis trackers comprising: an articulating mast connected to amobile machine; a rotary driver positioned on and operable to travelalong a drive axis of the articulating mast; a positioning system forlocating the drive axis of the mast within a coordinate system; amicrocontroller connected to a plurality of motion controllers to effectmovement of the articulating mast, wherein the microcontroller isprogrammed to control the plurality of motion controllers to orient themast to align the drive axis of the mast with a desired drive axis andto control the rotary driver to drive a first foundation component intounderlying ground along the desired drive axis; and an alignment jigpositioned on the mast for holding a second foundation component at aposition in the coordinate system with respect to the driven firstfoundation component at a predetermined point in space.
 12. The systemaccording to claim 11, wherein the microcontroller is programmed toautomatically control the plurality of motion controllers to orient thealignment jig with respect to the first foundation component and thepredetermined point in space to enable a third foundation component tointerconnect the first foundation component to the second foundationcomponent after the first foundation is driven.
 13. The system accordingto claim 12, wherein the predetermined point in space is an approximatecenter of a tracker torque tube that will be supported by the secondfoundation component.